Bone fixation devices are useful for promoting proper healing of injured or damaged vertebral bone segments caused by trauma, tumor growth, or degenerative disc disease. The external fixation devices are commonly utilized to immobilize the injured bone segments to ensure the proper growth of new osseous tissue between the damaged segments. These types of external bone fixation devices often include internal bracing and instrumentation to stabilize the spinal column to facilitate the efficient healing of the damaged area without deformity or instability, while minimizing any immobilization and post-operative care of the patient.
One such device is an osteosynthesis or bone fixation plate, which can be used to immobilize adjacent vertebrae. Typically, the fixation plate is a rigid metal or polymeric plate positioned to span bones or bone segments that require immobilization with respect to one another. The plate is fastened to the respective bones, usually with bone screws driven into the vertebral bodies. In this way, the plate is secured to the spine, fixing the respective vertebrae in a desired position. Bone plates can be useful in providing the mechanical support necessary to keep vertebral bodies in proper position and bridge a weakened or diseased area such as when a disc, vertebral body or fragment has been removed. Exemplary systems are disclosed in U.S. Published Application 2003/0187443 A1 to Lauryssen et al., U.S. Pat. No. 6,159,213 to Rogozinski, U.S. Pat. No. 6,152,927, U.S. Pat. No. 6,017,345 to Richelsoph, U.S. Pat. No. 5,676,666 to Oxland et al., U.S. Pat. No. 5,616,144 to Yapp et al., U.S. Pat. No. 5,549,612 to Yapp et al., U.S. Pat. No. 5,261,910 to Warden et al., and U.S. Pat. No. 4,696,290 to Steffee.
Accordingly, there exists a need for a plate system and method of placement of the same that provides the advantages of the currently available arrangements, while minimizing or eliminating the disadvantages of the same. There remains a need for an anterior bone plate system that minimizes any soft tissue and osseous tissue damage that would occur with its implementation, that is easy to use, and that provides the surgeon with flexibility in placement of the same. The system must be able to provide effective fixation and immobilization of vertebral bodies, while also providing for the subsidence necessary for proper fusion and prevent axial extension of the plate. The invention provides such an arrangement. The advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.